The Comet, a 337-ton sidewheel steamer, was built in 1848 at Portsmouth, Ontario, by shipbuilder George N. Ault. She is 174 ft (53.5m) in length and has a beam of 24 ft (7.4m). She was unique as she was powered by two "walking beam" type steam engines with a 51-inch piston. She was a passenger steamer much used by travellers, but after a few short trips she struck a shoal in the St. Lawrence river and sank. She was raised, repaired and put back into service. In 1849, a burst steam pipe seriously injured three Irish firemen, two of them fatally. Then, in 1851, after being damaged by a boiler explosion during her departure from Oswego, New York, she was rebuilt and renamed the "Mayflower".

One gusty spring evening in May 1861, on her first voyage of the season, the steamer left Kingston for the last time. Strong winds were out of the southwest as she cleared Nine Mile Point off the westerly end of Simcoe Island. The Comet altered course toward Timber Island under Captain Francis Paterson to give wide berth to three sailing ships on the horizon. An hour later, the Comet and the schooner "Exchange" collided when the Exchange attempted to run for safe harbor from the storm. Both ships attempted to stay close to help out the other but the wind took the schooner out of hailing distance. The Comet kept its steam engines running and, in an attempt to make shore, managed to travel to within 2 miles (3.2km) of Simcoe Island before the captain had crew and passengers abandon ship in lifeboats. Two crewmen were lost trying to bail out the large yawl which the Comet towed astern. The survivors were set safely ashore on Simcoe Island, while the Comet sank about 1.5 miles (2.4km) off the Island in about 90 ft (28m) of water.

Divers Jim McCready and Dr. Robert McCaldon rediscovered the Comet, noted for her bad luck, on September 7, 1967. The two were hobby divers who had been looking for this particular wreck for the previous 10 years. Many artifacts were salvaged, including a brass door latch, a brass wine barrel spigot, silver spatulas, English ironstone pitchers, wash basins, cups, saucers, bowls and hand-blown glass goblets, some of which are in the Marine Museum of the Great Lakes. There was some discussion of raising the Comet but this never came to pass.

The Comet lies in 90 ft (28m) of water, with her paddlewheels still upright, though much of the top decking has collapsed. For those trained and experienced, penetration below deck is possible at the stern for a view of the boilers and the engines. Good buoyancy is important as silt can be stirred very quickly making it difficult for the next diver to see. There are also some plates and cups left on the decking, completing the underwater museum.

The Comet is a spectacular example of ships of her time and is a special favorite of divers who visit her. Of consideration to the recreational diver is time because of her depth. There is little current on her, and visibility is usually 20 to 50 ft (6-16m), with upwards of 80 ft (25m) in the spring and fall.